Source:http://linkedlifedata.com/resource/umls/id/C0460002
UWDA: Anatomical structure, which consists of members of predominantly one organ subclass; these members are interconnected by zones of continuity. Examples: skeletal system, cardiovascular system, alimentary system.,FMA: Anatomical structure, which has as its direct parts instances of one or more organ types which are interconnected with one another by zones of continuity. Examples: skeletal system, cardiovascular system, alimentary system.,NCI: An anatomical structure that consists of organs and organ subclasses responsible for certain body functions. Representative examples are the gastrointestinal system, urinary system, and hematopoietic system.